Ask HN: Best Developer Linux Laptop in 2012

I'm looking to buy a new machine for work. I've found some old threads discussing laptops for Ubuntu, but now it's 2012, the world has changed, there are even Macbooks with retina display... I really don't want to use OS X, I've been using it for about two years, but since I've installed Ubuntu on my MacBook Air I'm happier than ever.

So I'm looking for a powerful laptop around 13" and fully Ubuntu compatible. And the most important thing is that it shouldn't be heavy brick; I used to work with a MBA and really liked the ease of it.